Joshua p



(No Model.)

. J. P. MOCOOK.

BALANCED SLIDE VALVE.

No. 289,678. PatentedDeo. 4,1883.

- it WM,

Amonmrs.

n. m. Photo-Lithographer. Wflhinlbn. n4 1:.

UNITED STATES PATENT OFFICE.

JOSHUA I. MOOOOK, OF RICHMOND, VIRGINIA, ASSIGNOR OF ONE-THIRD TO JAMES H. BRUCE,

OF SAME PLACE.

BALANCED SLI DE-VALVE.

SPECIFICATION forming part of Letters Patent No. 289,678, dated December 4.; 1883.

Application filed May 5, 1883. (No model.)

To aZZ whom, it mag concern.-

Be it known that I, JOSHUA P. McGooK, of Richmond, in the county of Henrico and State of Virginia, have invented a new and useful Improvement in Balanced Valves; and I do hereby declare that the following is a full, clear, and exact description of the same.

This invention consists, mainly, in the combination of a slide-valve of proper construction with a shield-plate of special form.

It consists, further, in certain details of construction, which, in connection with the foregoing, will be fully described hereinafter.

In the accompanying drawings, Figure 1 is a sectional elevation in line 00 a: of Fig. 2. Fig. 2 is a top view with cover removed. Fig. 3 is a perspective view of false seat.

A represents a steam-chest of the ordinary construction, havingthe valve or false seat'a, which serves as the seat for the valve, provided with exhaust and live steam ports, in the m anner well understood.

a a represent square pieces of metal, solid or attached, according as a new or false valveseat is used, said pieces of metal aapbeing located at the corners of the valve-seat a, and

having their bearing-faces in the same horizontal plane as the face of the valve-seat.

B represents an open-back or two-faced valve, which is connected by an ordinary valve-yoke, b, as shown, and reciprocated in the usual manner.

0 represents a solid shield-plate having on the bearing-face an elongated recess of the same length and width as the exhaust-port. which shield-plate is supported by means of curved bars 0 c, the ends of which formfeet adapted to rest upon the metal pieces a a of the valve-seat a.

0 represents a spring located upon and attachedto the top of the shield-plate andadapted to press against the under surface of the lid of the steam-chest, forthe purpose of keeping the shield-plate in proper position when the steam-chest is-located on the side of cylinder. The area of the shield-plate face equals the area of the valve-seat face, and when the parts are adjusted together .in the chest the recess in the face of shield-plate is opposite the exhaust-port, which prevents wearing shoulders or ridges by the valve.

. The operation issubstantially as follows: As the valve moves backward and forward in the manner well understood, the shield-plate O has a very slight movement in the same way upon its bearings a a. The object of this movement is to produce wear at the feet or bearings of the shield-plate to compensate for wear between the shield-plate and valve, and thus keep the adjustment of said parts steamtight. The valve itself, as it reciprocates when the throttle-valve is closed, will not jump, as the ordinary valve does, the back -pressure causing the shield-plate to rise, thus releasing the valve and suction of piston.

Among the advantages of the described construction are the following, viz: An engine having my valves and carrying one hundred and thirty pounds of steam to the square inch can easily be reversed at full throttlea result difficult and generallyimpossible with the ordinary valves. The wear on the eccentrics, links, rocker-boxes, valves, and valve-faces is greatly reduced and the engine much more easily handled. The shield-plate supports the entire pressure on the top of the valve, and the pressure being equal on the sides of the valve causes the valve to be very nearly balanced, the preponderance which is at the lead or crack of the port being in favor of valve.

Having thus described my invention, what I claim as new is 1. In combination with the valve -seat a, having the corner-pieces aa solid or attached, the open-back two-faced valve B and shieldplate 0, with its elongated recess and bars 0 0, with feet adapted to rest upon and slightly move on said corner-pieces a a with reciprocation of valve, as described.

2. In combination with the plate a, the open backed valve B and shield-plate G,with curved bars 0 c and spring 0, as and for the purpose described.

JOSHUA P. MOOOOK.

Witnesses:

W. H. GLAZEBROOK, W. H. BARRETT. 

